The present invention relates to pulleys and, more particularly, to a pulley block assembly for releasable attachment to a sheet end and requiring no overhang beyond the sheet end comprising, a first pulley block housing having planar, parallel, spaced side portions and including a first half of interconnection means for releasably interconnecting the first pulley block housing in side-by-side parallel relationship to a second pulley block housing; a first pulley roller rotatably mounted between the side portions of the first housing so that a line can pass over the first pulley roller; a second pulley block housing having planar, parallel, spaced side portions and including a mating second half of the interconnection means disposed for interconnecting the first and second pulley block housings, the interconnection means including interconnecting means for attaching the sheet to and between the first and second pulley blocks; and, a second pulley roller rotatably mounted between the side portions of the second housing so that a line can pass over the second pulley roller.
Windsurfing has become a highly popular and competitive sport within recent years. As with most competitive sports, competition equipment is highly refined to provide peak performance. A basic sailboard is shown in FIG. 1 wherein it is generally indicated as 10. Sailboard 10 comprises a board 12 upon which the sailor stands. A mast 14 extends upward from the board 12 and a boom 16, as shown enlarged in FIG. 2 in top view, extends backward from the mast 14. Unlike a sailboat where the boom is a single member under which the occupant sits, the boom 16 of the sailboard 10 is gripped by the sailor in a standing position. A sail 18 extends from the mast to the rear of the boom 16 with its clew located generally in the area indicated as 20. As can be seen, it is popular and convenient to have the boom 16 of a "wishbone" shape with gripping arms 22 on either side of the sail 18. As the sailor changes direction, he or she can swing in front of the mast 14 to stand on the proper side of the board 12 relative to the wind position and grip the appropriate arm 22.
Sail performance is enhanced by having the clew 20 of the sail 18 extend all the way to the end of the boom 16. Employing prior art methods and apparatus for adjustably attaching the clew 20 to the boom 16 has required sailors to choose from the following non-ideal situations. The outhaul line could be reeved directly through a grommet in the sail at the clew, which allow the sail to be pulled to the boom end; but, creates high friction, which makes it difficult to place adequate tension on the sail. Additionally, that approach requires that the line be reeved through the sail grommet each time the sail is rigged or changed, which is tedious and time consuming. A pulley system can be attached permanently to the sail clew. This allows the sail to be pulled to the end and reduces friction; but, as in the previous approach, requires that the outhaul be reeved each time the sail is rigged or changed. Finally, one could use a pulley/hook combination as is known in the prior art; but, which increases the gap between the sail and boom end to up to two inches.
The typical prior art pulley arrangement is depicted in simplified form in FIG. 2. A first pulley 26 is attached to the clew 20 of the sail 18, either permanently or with a releasable hook arrangement, and a second pulley 28 is attached to the end of the boom. The two pulleys 26, 28 are reeved with line 30 as appropriate for the particular configuration whereby the outhaul of the line 30 can be pulled in the direction of arrow 32 to pull the sail 18 taut. Such prior art apparatus for adjustably connecting the sail 18 to the boom 16 is large and cumbersome. Moreover, sailboards are generally disassembled when carried on cartop roof racks, and the like, and, therefore, the ability to easily disassemble the interconnections between the parts is an important consideration. In the prior art, not only are the boom-to-sail connections large and cumbersome, they are also typically complex and not easily disassembled.
A more detailed understanding of the problem to which the present invention is directed can be seen, for example, with reference to U.S. Pat. No. 4,365,570 of Jamieson; U.S. Pat. No. 31,167 of Schweitzer, et al.; U.S. Pat. No. 4,436,047 of Freyrie; European Pat. No. 0 071 253 of Brittinger and European Pat. No. 0 021 447 of Nieschler.
What is desirable is an apparatus which combines low friction, virtually no gap between the clew and boom, and quick attachment and detachment without the necessity for rethreading of lines each time.
Wherefore, it is the object of the present invention to provide a miniature pulley block assembly for attaching a sail to the end of a boom in a minimum distance.
It is another object of the present invention to provide a miniature pulley block assembly for a sailboard wherein the components thereof are releasable from one another whereby the sail is easily disassembled from the boom end.
Other objects and benefits of the present invention will become apparent from the detailed description contained hereinafter taken in conjunction with the drawing figures which accompany it.